"Dynamic bending of a fuel rod. Motion equation."

Verhoglyadov A.E.

In the process of working on the project of a new NEPTUN pulsed reactor, the phenomenon of dynamic bending was discovered – a feature of the dynamics of pulsed reactors that does not appear in reactors of other types, but plays a significant role in evaluating the stable operation of the reactor. Movement of fuel elements (fuel rods) under the influence of periodically changing temperature can lead to high changes in reactivity and fluctuations of the reactor power. To accurately simulate the operation of the reactor, it is necessary to know the shape of the fuel element at the time of the next power pulse. Since numerical methods for solving this dynamic problem of thermoelasticity require too much computation time, an analytical method was applied.
The report will present the first results of the numerical-analytical solution of the equation of forced oscillations of a fuel rod, as well as the prospects for using the method in studying the dynamics of the NEPTUN reactor.